Materials : Metals and Non-metals Class 8 Notes CBSE Science Chapter 4 (Free PDF Download)

Introduction

• All the things around us are made up of materials that are either metals or non-metals. 

• The metals are those materials that are strong and possess certain characteristic properties which make it suitable for use in almost everything. Some examples are iron, copper, zinc etc.

• They can be found in household articles, vehicles, machines, buildings, utensils etc. 

• Non-metals are those materials that don’t possess these characteristic properties. Some examples of it are sulphur, carbon, oxygen etc.

Physical Properties of Metals

• The metals have a property that allows them to be beaten into thin sheets. This property is termed as malleability. This allows a material to change its shape and be made into thin sheets like silver foil or aluminium foil. 

• The metals also have a property that allows them to be drawn into wires and this property is termed as ductility. It is this property that allows metals like copper to be drawn into wires.

• The metals are very good conductors of heat and thus they are used for making cooking utensils, irons, heaters, etc.

• The metals are also good conductors of electricity due to which metals like copper and aluminium are used for making electric wires and cables.

• The metals have a unique property to make a ringing sound when they are struck hard. This is termed as being sonorous. It is due to this property that you hear a sound when you hit a metal surface. 

• Some of the metals have a shiny or lustrous appearance like gold, silver.

Chemical Properties of Metals

• The metals react with oxygen and they produce metal oxides that are basic in nature. We can see that a red litmus paper introduced into a solution of rust, (which is basically a metal, iron), turns blue indicating the formation of a basic metal oxide. 

• Some of the metals react strongly with water like sodium due to which it is kept in kerosene and some react very slowly like iron. In general, the metals react with water to form  metal hydroxides and hydrogen gas.

• The metals react with acids to form metal salts and hydrogen gas. If a burning matchstick is brought near the mouth a test tube containing magnesium ribbon and dilute hydrochloric acid, you hear a pop sound due to the burning of hydrogen gas, which is formed in the reaction.

• Some of the metals like aluminium and zinc react with bases like sodium hydroxide to produce metal salts and hydrogen gas which burns with a pop sound.

• The metals have a tendency to displace more reactive metals from the less reactive metals in their compounds in their aqueous solutions. We can see that the blue colour of an aqueous solution of copper sulphate and zinc disappears and a red deposit is seen at the bottom. This is because zinc is more reactive than copper replaces it and forms zinc sulphate and the red copper is released.

Uses of Metals

• Metals are used in the manufacture of equipment, machines, aeroplanes, automobiles, nails etc. because of their strength and durability.

• The metals like gold, silver are used for making jewellery due to its lustrous properties.

• Metals like copper and aluminium are used to make wires due to ductile property and them being good conductors of electricity.

• Metal like mercury finds its use in thermometers.

• Metals like nickel, chromium are used in the electroplating and steel industry.

• Metal like lead is used to manufacture batteries.

• Metals like aluminium are used as packaging material as it can be rolled into sheets.

Physical Properties of Non-Metals

• The non-metals are non-malleable as they are brittle and break into a powder when they are beaten. Like sulphur turns into a powdery mass. 

• The non-metals are also not ductile as they can’t be drawn into wires, except for carbon. Carbon fibres are used in sports and music equipment.

• The non-metals are bad conductors of heat and electricity with the exception of graphite, which is the only non-metal to conduct heat and electricity.

• The non-metals are not sonorous and do not produce any sound on being struck. A wooden box does not make a ringing sound when struck.

• The non-metals are non-lustrous, that is they are soft and dull in their appearance like charcoal.

Chemical Properties of Non-Metals

• The non-metals generally react with oxygen and produce non-metallic oxides which are in turn acidic. We can see that sulphur reacts with oxygen to produce sulphur dioxide gas. And if this is dissolved in water, it will lead to the formation of sulphurous acid which will turn blue litmus paper to red, indicating its acidic nature.

• The non-metals generally do not react with water though they may be highly reactive in air. Like phosphorus which is stored in water as it is highly reactive when exposed to the oxygen in the air. 

• The non-metals generally do react with any of the acids.

Uses of Non-Metals

• One of the most important non-metal, oxygen is essential for our survival and similarly carbon for the plants.

• Non-metals like nitrogen, phosphorus are used widely in fertilizers.

• Non-metal like liquid hydrogen is used to propel rockets.

• The non-metal graphite is quite indispensable in pencils.

Easy Revision Techniques for Class 8 Science Chapter 4 Notes

Class 8 Science Chapter 4 Metals and Non-metals Notes - Summary

This is the 4th chapter of the Class  Science syllabus. It will discuss what metals and non-metals are along with proper descriptions and examples. Every feature will be properly demonstrated using the right illustrations. Previously, students have studied metals and non-metals in a simpler version. This time, it will take you a little deeper into the concepts. You will have to figure out how to prepare the chapter by going through the chapter properly and refer to Class 8 Science Metals and Non-metals notes accordingly.  Let us check how the revision notes can help students to study this chapter.

In the introduction part, you will find how the metals and non-metals are being illustrated using their physical and chemical properties. If you refer to these properties in the Class 8 Science Notes Chapter 4, you will understand how metals behave in different physical and chemical conditions. Proceeding further, you will study the chemical and physical properties of non-metals. Figure out the differences between these two types of elements by comparing these properties. As per the experts, this is the best tip to remember how metals and non-metals vary. You will also have the Ch 4 Science Class 8 notes to refer to and make it easier for you to prepare.

In Class 8 Science Ch 4 notes, every concept has been explained simply to help students understand it properly. You will learn the reasons for the properties of metals. It all depends on the number of valence electrons present in the outermost shell and the mass number of the elements. Even if the metals are characterized by some common properties, you will discover some exceptions. Every exception will be explained using proper examples so that you can remember them during an exam. Find the proper illustration of these concepts in Metal and Non-Metal Class 8 notes.

The most challenging part of this chapter is to understand and remember the chemical properties along with the examples of chemical equations. As per Science Chapter 4 Class 8 notes, study the equations and explain the properties of the metals and non-metals on your own. It will help you to overcome the doubts on the first go.

In Science Class 8 Chapter 4 notes, you will also learn different reactions and their respective equations too. These reactions should be studied so that you can use them to define the chemical properties of metals and non-metals. It might be tough to comprehend these reactions. It is better to follow Class 8th Science Chapter 4 notes to study the reactions and their features.

Why Use Vedantu’s Chapter 4 Science Class 8 Notes?

The prime reason for using Materials Metals and Non-metals Class 8 notes is its clarity and ease in understanding the concepts. The expert teachers have used the simplest ways to describe the concepts so that every student can finish revising the chapter faster.

Conclusion

Vedantu's Materials: Metals and Non-metals Class 8 Notes for CBSE Science Chapter 4 provide an invaluable resource for students exploring the world of chemistry. The comprehensive and concise content covers the fundamental concepts of metals and non-metals, making learning engaging and effective. The free PDF download is a commendable initiative, ensuring accessibility to all learners. With clear explanations, illustrative examples, and relevant diagrams, these notes foster a deeper understanding of the subject matter. Vedantu's commitment to providing quality educational materials empowers students to excel in their academic journey. Embracing these notes equips learners with the knowledge and confidence to grasp the intriguing properties and applications of metals and non-metals.